Flexible ladder



Aug. 19, 1952 w. WILLIAMS Er AL FLEXIBLE LADDER Filed A rile, 1948 M0250 [Val/Ins! Jrxwli) 0. $7000 atented Aug. 19, i952 FLEXIBLE LADDERWilfred Williams, Oldham, and Stanley David Studd, Stockport, EnglandApplication April 6, 1948, Serial No. 19,314 In Great Britain October29, 1947 11 Claims. (01. 228-44) 4 1 This invention relates to animproved flexible ladder, which is intended primarily, though notexclusively, as a fire-escape appliance.

In this connection, the known form of rope ladder, whilst possessing theobvious advantage that it can be stored in a relatively small space (forexample in a box immediately below the se-.

lected escape window), with one end anchored within the building, andready to be put in position merely by throwing the free end out of thewindow, has two major disadvantages; i. e.

(1) It is, not fireproof and may b rendered useless before or duringuse; and

(2) Its liability to swing about freely calls for considerable skill andpractice to find and engage the rungs with the feet, especially as thereis nothing to prevent the ladder from lying fiat against the wall of thebuilding. In fact the natural consequence of the forces exerted duringuse of the ladder is for the rung which bears the bulk of the usersweight to be forced nearer the wall than the next higher rung or thatportion of the side rope which is being held by the hand. For thesereasons rope ladders are not generally approved as a fire escapeappliance.

The object of the present invention is an improved fiexible ladder,capable of being folded into a relatively small compass and in which theaforesaid disadvantages of a rope ladder have been eliminated.

The invention is illustrated with reference to the accompanyingdrawings, wherein:

Fig. 1 is a fragmentary perspective view showing one form of theimproved ladder extended down the wall of a building.

Fig. 2 is a similar view showing, to an enlarged scale, a detail of Fig.1.

Fig. 3 is a perspective view illustrating the der of Fig. 1 fullycollapsed Within thebuilding.

Fig. 4 is a fragmentary perspective view of a lad modified constructionof ladder showing the manner of folding.

In the example illustrated in Figs. 1-3, the side members of the ladderare of metallic chain-like construction, each comprising a plurality ofmain links A connected end-to-end through the medium of interposed shortlinks B of U section, the various pivotal connections being effected bymeans of rivets C and/or bolts D.

The.,U section of each short link B embraces the ends of the adjacentmain links A, and a1- ternate links B in each side member are arrangedwith their sections facing in rections as shown.

Conveniently the main links A are formed as opposite diflat metalstrips,-say by /8 inch in section and measuring about 5 inches betweenthe centers of the rivetor bolt-holes near their 'ends:1 The short links13 may be produced by suitably folding rectangular blanks of sheet metalof, say, 0.08 in. thickness and the holes therein may be arranged withtheir centers about 78 inch apart."

The two side members are of identical con-Q struction and each shortlink B of one such niem-" her is connected by a rung E to thecorresponding link of the other side member.

Each rung E is formed by pressing a narrow rectangular blank of sheetmetal into channel form, the edges of the channel being preferably.

turned inwards or, folded over, as at F, to provide the requisitestiffness. Convenient dimensions for the channel so produced are 12inches lon 1 inch in width, and inch in depth.

The inner faces of two of the short links B are rigidly united, as bywelding, to the ends of each rung channel, associated with which is awall engaging member. This latter may be formed by bending a strip ofmetal into the general shape of the letter W, the extremities of thestrip abutting the short links B aforesaid and the central link beingengaged between the side walls of the channel, which may deform as at Hto retain it. The rung E is fixed to the opposed links B in alignmentwith corresponding holes in the latter, and the rivets C (or theirequivalent) which engage in such holes are preferably passed alsothroughv the extremities of the wall engaging member G (see Fig. 2).Conveniently the member G is formed from strip about 4 inch wide by 0.08inch thick, its

length being such as to provide two angular loops projecting about 4inches from the base of the rung channel. These loops (represented bythe two halves of the letter W) are preferably flattened at their outerends, and the central part of the member G within the rung channel maybe similarly flattened.

When in use against the wall I of a building, the ladder is suspendedwith its rungs E at the upper ends of the associated links. B and withthe members G projecting towards the wall aforesaid, so that under theweight of a person standing on the ladder, they bear against such walland serve to space the rungs E therefrom as shown in Fig. 1. Therule-joint action between the connected links A, B, effectively preventsany appreciable tilting of the rungs E and wall-engaging members G whenunder load.

Their construction permits the side members of the ladder to fold inzig-zag formation and to be collapsed into a stack as shown in Fig. 3,the main links A under these conditions being in superposed edge-to-edgerelation whilst the short links B are disposed at right angles theretoand end-to-end with one another.

Owing to the manner in which the side members fold up, and the fact thatthe main links A are longer than the projection of the wall-engagingmembers G from the rungs E, alternate members G are disposed one aboveanother within the rectangular stack, while the remainder projectoutwardly thereof, two walls of the said stack being formed by thesuperposed rungs E.

The pair of main links A which are uppermost when the ladder is extendedare preferabl connecte'd'to the ends of a pair of plate-link chains Jadapted to extend in laterally spaced relation the same time, ofavoiding any considerable slackness of such chains when the links'inv'question are resting on the floor N (Fig. 3

With the arrangement above described, the suspension chains J ensurethat the parts of the collapse'diladd'er are automatically stacked closeto 'the'wall I, the superposed members G which project outwardly fromthe stack being disposed as close as possible to the inner face of'suchwall and between the. chains J as they hang from the brackets L.

Toextend the ladder it is merely necessary to throw the stacked elementsout of the window, whereupon the weight of the rungs E and associatedparts will automatically bring "the links A of each side member intomutual alignment and eventually drag the suspension chains J into anoperative position across the window-sill K.

To prevent the adjacent members G from catching on the internalwindow-ledge O and sill K as the ladder unfolds, some form of temporaryguiding means may be provided. For example, a suitably curved tube orrail (indicated at P in Fig. 1) may be detachably mounted adjacent theposition of the stacked ladder so as to form a chute extending upwardlyand outwardly over'thewindow-ledge O and sill K, Conveniently a spigot Qon the chute member P is en gaged in a socket R carried by the anchorageplate M, a bracket S on which provides a seating for the lower end ofthe chute member P and serves to maintain the latter erect.

The use of a chute as above described greatly facilitates and eXpeditesthe extension of the ladder, inasmuchas it is only necessary to lift theuppermost adjacent rungs E andtoslide them along the tube or rail P withtheir wall-engaging members supported astride the latter. As soon as theend portion of the ladder is hanging freely, its weight will cause therest of the ladder to be dragged out of the window, unfolding as itgoes. The chute member P will then, of course, normally be dismounted.

Corresponding links of the suspension chains J may be connected bytubular or other cross-members adapted to provide a secure grip for aperson climbing over the window-sill, and washers or collars ofrelatively large diameter may be attached to the chain links so as tocause these cross-members to stand well away from the surface of suchsill.

The bottom rung of the ladder, which becomes the top rung when theladder is collapsed, may beprovided with a harness or cradle in which achild may be secured and lowered by unfolding the ladder.

The collapsed ladder may be housed in a sheet- J metal or other casing Tof suitable dimensions, such casing being secured to the wall I and/orthe floor N and having a removable lid U.

It will be appreciated that the height of the stack into which theladder collapses is determined by the number ofmain links A in each-sidemember thereof and the individual widths of such links.

When the variousparts are made to the dimensions previously quoted, a 30foot ladder maybe folded into a stack'measuring approximately 12 incheswide, 15 inches deep, and 30- inches high.

In the event of the available floor-space being limited, the depth ofthe stack from front to rear may be reduced employing themodified-construction shown in Fig. l. 7

In this modification, the main links are made only about half the lengthof those used in the preceding construction, the pairs of links Bassociated with two consecutive rungs'E being connected by two pairs ofsuch main links and a third pair of short links B whose U sections faceoppositely to those of the rung-carrying links B. The side members ofthe modified ladder foldin zigza-g formation as previously described,but in this case, all the superposed members Gare disposed within thestack, which is U shaped, instead of rectangular, in plan view. 7 V Withsuch an arrangement, the overall depth of the stack is approximatelyhalved, but on theother hand its height is proportionately increased, sothatthe preceding construction is preferred unless the window-ledge O isunusually high above the floor N. What we claim is: 1. A flexible laddercomprising collapsible side members, a plurality of rungs connected attheir ends to said side members, and wall-engaging members connected tosaid rungs intermediate said side members and longitudinally ofsaidrungs, said wall-engaging members having two angular loops projectingfrom said rungs and flattened at the outer ends thereof, said;wallengaging members being constrained, on extension of the ladder, toassume an operative position outstanding from the line of rungs. I

2., A flexible laddercomprising a plurality of links connectedtogether'to form two-chain-lik-e assemblies serving as the side membersof theladder, a plurality of rungs each connected at its ends tocorresponding links of said two cha-iI I-; like assemblies, andwall-.engaging members connected to said rungs intermediatesaidsidemembers and longitudinally of said rungs, said Wallengagingmembers having two angular loops'projecting from said rungs andflattened at the outer having their sections-directed oppositely to theother short links of the same side member, a plurality of rungs eachrigidly united at its ends to, corresponding short links of said twoside members, and wall-engaging members rigidly mounted upon said rung-sso that, on extension of the ladder, they automatically assume anoperative position outstanding from the line of rungs, the completeladder being foldable in zig-zag formation with the main links of eachside member mutually superimposed and the rungs and wall-engagingmembers similarly stacked between the folded side'members.

4. A flexible ladder comprising two chain-like side members eachconsisting of main links of equal length connected by short links, eachof said short links having a U section which embraces the ends of theadjacent main links and alternate short links having their sectionsdirected oppositely to the other short links of the same side member, aplurality of rungs rigidly united at their ends one to each pair ofcorresponding short links in said two side members, and wall engagingmembers rigidly mounted upon said rungs so that, on extension of theladder, they automatically assume an operative position outstanding fromthe line of rung ,by an amount not exceeding the length of a main link,the complete ladder being fol-dable in zig-zag formation with the mainlinks of each side member mutually superposed and with alternate rungsand associated wall-engaging members disposed in two spaced stacks.

5. A flexible ladder comprising two chain-like side members eachconsisting of main links connected by short links each of said shortlinks having a U section which embraces the ends of the adjacent mainlinks and alternate short links having their sections directedoppositely to the other short links of the same side member, a pluralityof rungs rigidly united at their ends to corresponding alternate shortlinks in said two side members, and wall-engaging members rigidlymounted upon said rungs so that, on extension of the ladder, theyautomatically assume an operative position outstanding from the line ofrungs, the complete ladder being foldable in zigzag formation with themain links of each side member mutually superimposed and the whole ofthe rungs and wall-engaging members similarly stacked between the foldedside members.

6. A flexible ladder comprising two chain-like side members eachconsisting of main linkconnected by short link-s, each of said shortlinks having a U section which embraces the ends of the adjacent mainlinks and alternate short links having their sections directedoppositely to the other short links of the same side member, a pluralityof rungs rigidly united at their ends to corresponding alternate shortlinks in said two side members, and wall-engaging members rigidlymounted upon said rungs and directed similarly to the sections of theshort links carrying the latter, so that they automatically assume anoperative position outstanding from one face of the: ladder when thesame is extended, the. complete ladder being. foldable'in zig-zagformation with the main links of each side member mu-,

tually superimposed and the whole of the rungs and'wall-engaging memberssimilarly stackedbetween the-foldedside members.

7. A flexibleladder comprising collapsible side members, a plurality ofvchannel-section rungs connected at their ends to said side members andwall-engaging members in the form of stripmetal loops rigidly'mountedone in each rung channel, the arrangement being such that, when theladder is extended, the various wall-enga ing members automaticallyassume an operative position outstanding from the line ,of rungs.

8. A flexible ladder comprising collapsible side members, a plurality ofchannel-section rungs connected at their ends to said side members andstrip-metal members of W shape each having its extremities rigidlymounted in one of the rung channels, the arrangement being such that, onextension of the ladder down a wall, said rungs automatically assume anoperative position with the projecting parts of said W-shaped membersthereon bearing against the wall.

9. A flexible ladder comprising a plurality of links connected togetherto form two chain-like assemblies serving as the side members of theladder, a plurality of rungs each connected at its ends to correspondinglinks of said two chainlike assemblies, wall-engaging member connectedto said rungs intermediate said side members and longitudinally of saidrungs, said wallengaging members having two angular loops projectingfrom said rungs and flattened at the outer ends thereof, saidwall-engaging member being constrained, on extension of the ladder, toassume an operative position outstanding from the line of rungs,anchorage means for location within a building including a plate securedto a wall of said building beneath a window and anchoring brackets atthe ends of said plate, and suspension members connecting the end linksof the ladder to said anchorage means and adapted to lie over awindow-sill of the building when the ladder is hung externally of thelatter.

10. A flexible ladder comprising a pluralityoi links connected togetherto form two chain-like assemblies serving as the side members of theladder, a plurality of rungs each connected at its ends to correspondinglinks of said two chainlike assemblies, wall-engaging members connectedto said rungs intermediate said side members and longitudinally of saidrungs, said wall-engaging members having two angular loops projectingfrom said rungs and flattened at the outer ends thereof, saidwall-engaging members being constrained, on extension of the ladder, toassume an operative position outstanding from the line of rungs, spacedanchorage brackets adapted for location within a building, and furtherchainlike assemblies connecting the end links of the ladder one to eachof said brackets and adapted to rest upon a window-sill of the buildingwhen the ladder is hung externally of the latter.

11. A flexible ladder comprising a plurality of links connected togetherto form two chain-like assemblies serving as the side members of theladder, a plurality of rungs each connected at its ends to correspondinglinks of said two chainlike assemblies, wall-engaging members connectedto said rungs and constrained, on extension of the ladder, to assume anoperative position outstanding from the line of rungs, spaced anchoragebrackets adapted for location within 91 and suspension membersciofiiiecting' the and links 0f the ladder one te each oi said brackets,in combination with 'dismolmtabIe" guide means adapted to spam awindow-511101 the building while the: ladder is being extended down thewall of the latter and to support said wallengaging members cl'ear ofsaid-window+si11 dur- The following references are of record in the file0i this patent ing the progressiveimuvementof iahe ladder over' UNITEDSTATES PATENTS" Number- Number Name Date Huth June 12, 1877 Fall! Aug.1-4, 1877 Belches Apr. 30, 1889 Do'emer Apr. 1'0, 1894 D'odd Apr; 16,1901 Patterson Apr. 22, 19-19 Mowry Aug. 20, 1929 FOREIGN PATENTS ICountry Date Great B'rit-ain 1884 Great Britain r '18'86

